A note on the modes of the negative binomial distribution of order k, type I

Abstract: Upper and lower bounds are derived for the mode(s) of the negative binomial distribution of order k, type I, with parameters r and p, which are employed to establish an explicit formula for the mode(s) in terms of r and k when p equals 0.5. It is also shown as a direct consequence of the upper bound alone that the mode is k when r equals 1. The derivation of the bounds is based on a known recurrence relation satisfied by the probability mass function of the distribution.